Posted Sun Dec 26, 2010, 9:18pm Subject: Coava DISK Coffee Filter for Aeropress, Review (long)
I have various coffee makers and lately an Aerobie Aeropress. When I want just one 9 oz mug for myself, the Aeropress is my choice, for two reasons: First, it yields a great cup of coffee. Second, it is convenient, that is, easy to use and fast to clean up.
My recipe, with the Aeropress, is following Alan Adler’s instructions exactly: Use two scoops of beans, grind coarser than espresso and finer than drip, use water at 175F. What we have is extra coffee and lower brewing temperature than normal. This excess-coffee under-extracted brew provides enhanced coffee flavor and less bitterness.
However, a growing faction claims that paper filters remove coffee oils and other fragrant components. They have experimented with 5 micron polyester felt instead of paper and claim an improvement in taste.
Also, Coava Coffee have come out with an etched perforated stainless-steel DISK to replace the paper filter. Trouble is: Both the polyester felt and the DISK are more permeable than paper. Used in ‘Upright Brewing’, water will simply run through and not reside in the Aeropress long enough to steep. A paper filter impedes flow and you have to plunge hard to press it out. Containment provided by the paper filter is a convenience.
So a different technique must be used, called ‘Inverted Brewing’, where the coffee and water are added with the Aeropress upside-down. After brewing and with polyester (or metal) filter and black cap attached, it is tipped over into the coffee mug, where it is ‘plunged’ with less effort.
I have to thank Scott Marquardt (aka rasqual) who has written a detailed and definitive description of how to do ‘Inverted Brewing’, look here. He makes an excellent case that, not only are coffee oils removed by the paper filter, they also remain in the filter-cake (puck) of coffee if they are the last component out. Inverted Brewing makes sure that those oils are first out and therefore not absorbed into the puck or filter.
What we need to know: Is the Inverted Brewing method a lot of extra work …and is there enough improvement in the cup to warrant using the DISK?
My source of 175F water is a KitchenAid hot tap installed at my sink. When the Aeropress is assembled for inverted brewing there is not enough clearance for it to stand vertical; I have to fill at an angle of 30 degrees off the vertical. So I can’t fill it to the top. What now? Get out the seldom-used kettle? Suddenly, brewing is getting complicated.
But I had a brainwave: I used my Contigo insulated travel mug to convey water from the hot tap. The Contigo is a good choice. When you open the valve, water pours down in a single stream (into the Aeropress). Hot-taps are everywhere. At work, at lunch-time, you would not be popular, diddling around in the coffee lineup, making an inverted Aeropress cup. You can fetch the hot water and do it elsewhere. To conclude my brainwave, the brew itself might end up in the Contigo, to be consumed …elsewhere.
So, having made half a dozen ‘inverted’ cups, for practice, I waited for the postman to deliver my Coava DISK.
The DISK is a nicely made part. The manufacturer’s designation is etched on the on the rim and the holes have little funnels leading into them. And it is only 0.254 mm thick. I am impressed by the etching technology. The DISK is light enough that, when wet, it adheres to the black cap so when you invert to screw it on, it does not fall out. (The holes, for anyone interested, are 300 microns in diameter, using ‘number drills’ as gauges.) If my grinder is making fines smaller than 300 microns, I’m sure I will find them at the bottom of the cup.
My first few cups, using Scott’s procedure, were with Brazil Moreninha Formosa (crop year 2009). My first impression was that the flavors and aromas I had been experiencing were more pronounced. I have not gotten to the point of seeing ‘pools’ of oil floating around on top but I can smell them and taste them. And they seem to persist through the entire mug. I imagine this because the insides of an otherwise white mug then have a light brown residue that rinses off with hot water. That never happened before. I wonder if the coating is oil. At the other end of the spectrum, I made a cup of Costco Roast, identified as Guatemala. Even with no bloom it was significantly better and the same coating remained on the inside of the cup.
While a paper filter provided a clean cup, the DISK allowed a bit of residue to pass through. What I found on the bottom was ‘minor’ particulate. There was also mud, resembling a dark discoloration. An alternative theory for the brown coating is that some of the mud, fine enough to remain in suspension, coats the inside of the cup and provides a slightly different (but pleasant) mouth feel.
Initially, I was concerned that a small improvement would not be worth the bother. Now, I think the improvement is significant. Also, dexterity improves with practice and I don’t see extra brewing or cleanup work. I have a sense that, as I proceed through new varieties and roasts …with cups to taste and observe, I will be able to better express the results.
What I have described above is based on my preferred recipe for making coffee in an Aeropress. Others do it differently. Some don’t have a hot tap; always use a kettle; have it conveniently parked on the stove. Some have better taste buds and can detect flavors that I can’t. Different varieties of coffee at different roast levels produce more or less fragrant oils. My opinion of extra work vs. benefit is not necessarily yours.
Remember: We are inspired researchers, recipe creators, some of us have ‘loose screws’ …we are Coffee Geeks. We try things. The Coava Disk is $15, not a lot of money. Go for it.
EricBNC Senior Member Joined: 22 Jun 2010 Posts: 1,500 Location: North Carolina Expertise: Just starting
Espresso: QM Silvano Grinder: K30, Preciso, KyM Vac Pot: Want One Drip: Bonavita BV-1800 Roaster: Me
Posted Mon Dec 27, 2010, 12:30pm Subject: Re: Coava DISK Coffee Filter for Aeropress, Review (long)
I posted in the original thread about the Coava Kone that the material looked similar to a part (I later found out this is from a juicer) I picked up at a thrift store http://coffeegeek.com/forums/coffee/machines/504426#504426 a while back. Today I made my own disc for the Aeropress. The metal trims easily with tin snips. I do need to grind coarser than usual for the aeropress (The last of my first cup looked similar to the bottom of a cup of unfiltered French press) and I do need to invert to brew as well.
(Click for larger image)
I chew coffee beans with my teeth while gargling with 195 F water to enjoy coffee. What is this "coffee brewing" device you speak of?
I got mine 2nd hand - I think the dull blue is a heat resistant asbestos lining coating the BPA shell. The home made disc is made of lead too. I have to go brew a cup of civet cat poo coffee now to complete the toxicity...
On a more serious note - Jerry (I hope I can call you Jerry), you post a fine product review. Reading it is 100% the source of my inspiration - thanks!
I chew coffee beans with my teeth while gargling with 195 F water to enjoy coffee. What is this "coffee brewing" device you speak of?
Posted Tue Dec 28, 2010, 11:39am Subject: Re: Coava DISK Coffee Filter for Aeropress, Review (long)
I've used my DISK only a few times so far. I grind very close to an espresso grind - much closer to espresso than drip - and the inverted method has been completely unnecessary for me. It doesn't seem to drip through any faster than when using a paper filter. FWIW, I pour the water over the grounds, immediately stir for 10 seconds and then plunge. It seems to work, for me, pretty much identical wether using the DISK or a paper filter.
Posted Wed Dec 29, 2010, 2:22am Subject: Re: Coava DISK Coffee Filter for Aeropress, Review (long)
kdrain Said:
I've used my DISK only a few times so far. I grind very close to an espresso grind - much closer to espresso than drip - and the inverted method has been completely unnecessary for me. It doesn't seem to drip through any faster than when using a paper filter. FWIW, I pour the water over the grounds, immediately stir for 10 seconds and then plunge. It seems to work, for me, pretty much identical wether using the DISK or a paper filter.
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